linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / Documentation / watchdog / watchdog-api.txt

diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt
index 958ff3d..c5beb54 100644 (file)
--- a/Documentation/watchdog/watchdog-api.txt
+++ b/Documentation/watchdog/watchdog-api.txt
@@ -34,7 +34,19 @@ activates as soon as /dev/watchdog is opened and will reboot unless
 the watchdog is pinged within a certain time, this time is called the
 timeout or margin.  The simplest way to ping the watchdog is to write
 some data to the device.  So a very simple watchdog daemon would look
-like this source file:  see Documentation/watchdog/src/watchdog-simple.c
+like this:
+
+int main(int argc, const char *argv[]) {
+       int fd=open("/dev/watchdog",O_WRONLY);
+       if (fd==-1) {
+               perror("watchdog");
+               exit(1);
+       }
+       while(1) {
+               write(fd, "\0", 1);
+               sleep(10);
+       }
+}
 
 A more advanced driver could for example check that a HTTP server is
 still responding before doing the write call to ping the watchdog.
@@ -95,40 +107,7 @@ current timeout using the GETTIMEOUT ioctl.
     ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
     printf("The timeout was is %d seconds\n", timeout);
 
-Pretimeouts:
-
-Some watchdog timers can be set to have a trigger go off before the
-actual time they will reset the system.  This can be done with an NMI,
-interrupt, or other mechanism.  This allows Linux to record useful
-information (like panic information and kernel coredumps) before it
-resets.
-
-    pretimeout = 10;
-    ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
-
-Note that the pretimeout is the number of seconds before the time
-when the timeout will go off.  It is not the number of seconds until
-the pretimeout.  So, for instance, if you set the timeout to 60 seconds
-and the pretimeout to 10 seconds, the pretimout will go of in 50
-seconds.  Setting a pretimeout to zero disables it.
-
-There is also a get function for getting the pretimeout:
-
-    ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
-    printf("The pretimeout was is %d seconds\n", timeout);
-
-Not all watchdog drivers will support a pretimeout.
-
-Get the number of seconds before reboot:
-
-Some watchdog drivers have the ability to report the remaining time
-before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl
-that returns the number of seconds before reboot.
-
-    ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
-    printf("The timeout was is %d seconds\n", timeleft);
-
-Environmental monitoring:
+Envinronmental monitoring:
 
 All watchdog drivers are required return more information about the system,
 some do temperature, fan and power level monitoring, some can tell you
@@ -187,10 +166,6 @@ The watchdog saw a keepalive ping since it was last queried.
 
        WDIOF_SETTIMEOUT        Can set/get the timeout
 
-The watchdog can do pretimeouts.
-
-       WDIOF_PRETIMEOUT        Pretimeout (in seconds), get/set
-
 
 For those drivers that return any bits set in the option field, the
 GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current